Objective: To test the hypothesis that hyperinsulinemic obese subjects would respond differently to changes in the composition of hypoenergetic diets.
Design: A 4-week randomized dietary intervention trial.
Subjects: Thirteen male obese hyperinsulinemic normoglycemic subjects were divided into two groups and fed hypoenergetic diets providing 80% of their resting energy expenditure (REE). One group received a high-protein diet (HP; 45% protein, 25% carbohydrates, and 30% fat as percent of dietary energy) and the other a high-carbohydrate diet (HC; 12% protein, 58% carbohydrates and 30% fat).
Measurements: Anthropometry, body composition, fasting serum insulin and lipids, and REE were performed before and after the feeding period.
Results: Weight loss was higher in the HP than HC group (8.3+/-0.7 vs 6.0+/-0.6 kg, P<0. 05). There was a decrease in body fat in both groups, whereas body water decreased significantly more in the HP group. REE decreased more in the HC than the HP group (-384.3+/-84.6 vs -132.3+/-51.0 kcal, P<0.05). Serum total cholesterol, triglycerides and LDL cholesterol decreased significantly to a similar extent in both diet groups, while HDL cholesterol was decreased significantly only in the HP group. Mean fasting insulin decreased significantly in both diet groups and reached the normal range only in the HP group.
Conclusion: A low-carbohydrate (LC), HP hypoenergetic diet could be the diet composition of choice for a weight-reducing regimen in obese hyperinsulinemic subjects.